Effect of buffer strips on pesticide risks in freshwaters

Freshwaters and particularly small water bodies are constantly threatened by the use of pesticides in agriculture. These risks have to be mitigated and reduced according to the European Sustainable Use Directive. The creation of vegetated buffer strips is one measure to effectively mitigate the pesticide risk to freshwaters in agricultural landscapes. This study quantifies the buffer strip effects on pesticide risk posed by arable crop farming for German freshwaters using the pesticide risk indicator model SYNOPS. A constant but only slight turnover towards pesticides with lower water body distance requirements over time was observed when no buffer strips were present. However, the presence of buffer strips contributed to a much higher extent to pesticide risk reduction to freshwaters. The chronic risk to freshwaters was reduced by 29% (simulating 5 m buffer strips) and by 47% (simulating 10 m buffer strips). The effect of risk mitigation by buffer strips varied between crop type and pesticide type. Highest effects of buffer strips were achieved for herbicides and in oilseed rape. Overall, the results show that the creation of buffer strips is a crucial step to effectively mitigate pesticide risk to freshwaters in agricultural landscapes.